Embodiments of the invention pertain to databases that are maintained and contain data relating to roadway, waterway, off-road, track and other designated pathway systems that are used for transportation by powered vehicles. More specifically, embodiments of the invention relate to databases that are maintained and contain information concerning railroad track systems.
Railroad companies operate trains and control railroad traffic on track systems that may include thousands of miles of railroad tracks. In order to control the movement of trains on a track system, a track database is maintained that contains information relating to track topography, which is also referred to as the track profile data. The track profile data stored in these databases includes, among other things, grade data, track curvature data, and geographic coordinates of various points or segments of the track. Typically, a railroad track system is divided into geographic subdivisions, which include sets of railroad tracks extending between different train destinations. Within a subdivision, the railroad track may be segmented into track sections (that may include multiple tracks) of a predetermined length; and, for each track section there is provided one or more track grades or ranges of track grades. The track grade data for any one track section may be constant or it may have different grades in a single direction, grades in opposite directions have opposite signs, adjacent parallel tracks can have different grades or compensated grades including banking or super elevation curvature.
Geographic coordinates in the track profile data are typically provided in the form of a location of a point or section of the track and/or the identification of wayside traffic control devices or railroad crossings relative to mileposts (also referred to as “mile markers”) or other reference points positioned along the track. For example, a database may show that track T5 has a 1% track grade for 10 miles (16.09 kilometers) from mile post #75 to mile post #85 at which point the grade may increase to 1.1% for the next two miles from mile post #85 to milepost #87. In another example, the database may provide that switch A1 that connects track T5 to track T6 is positioned halfway between milepost #110 and milepost #111. The database may also provide coordinate or location data at discrete points along the track, for example location data relative to a start point, ending point, mile markers, switches, signal locations, etc.
In addition, the track database may include data relative to one or more civil speed limits associated with various track sections. Sometimes the track database may have temporary speed restrictions that may be imposed as a result for example of track repairs taking place on the track.
In use, the track database for a selected track or sections of track on which a train will be traveling is provided to an operator who prepares a trip plan based on the information provided in the track database. The operator, based on past experience and/or operating manuals, maps out a train route over the track sections provided. The route will include the identity of the different tracks the train will travel on and the different speeds at which the train will travel along the track. Given the track grade, and other parameters such as train weight and length, the operator is able to determine the locomotive throttle positions necessary to achieve the different desired speeds on the track, and plans the trip accordingly.
However, at times the data found in these databases is not complete, has not been updated, or is simply incorrect or inaccurate. In addition, locomotives may include one or more operating systems that provide for the automated control of certain locomotive functions. Such systems may include fuel savings systems, positive train control systems, brake control systems, and operator coaching systems, which use elements of the track database for the automated control of certain locomotive operations. The manufacturers or vendors of such systems provide relevant components of the track database; however, data conversion, human error, and other factors may lead to incorrect or inaccurate data entry.
In any such case in which the track grade is not correct the train may be traveling too fast on a track, which may result in an accident or inefficient use of fuel; or, the train may be traveling too slow, which may result in the train not meeting a time schedule. Moreover, if, for example, the data relating to the location of a switch is inaccurate, the train may enter the switch at too high a speed, which could cause an accident or derailment.